The invention is in the field of animal feeds. More specifically, the preferred embodiments of the invention are in the field of high-fat animal feed pellets.
It is desirable to provide an animal feed in the form of a formulated ration that contains desired and necessary nutrients. The preferred presentation of the formulated ration is in the form of a compact pellet. Such pellets are convenient for the operator to provide to the animal, and are palatable to the animal.
Often, it is desired to provide a high-fat animal feed in order to supply the animal with optimum nutritional energy. It is difficult, however, to incorporate high levels of fat into a pelletized formula. Specifically, when an animal feed pellet is formulated with a fat level greater than about 10% by weight, the intrapellet cohesive strength is substantially weakened, thereby making the pellet more likely to fracture and to create dust and wastage.
In recognition of this problem, the prior art has provided numerous pellet binders in an attempt to improve the intrapellet cohesive strength of animal feed pellets. For instance, the use of inorganic binders composed of calcium salts is taught in U.S. Pat. No. 4,988,520. U.S. Pat. No. 5,714,184 teaches the use of the digest of wood chips with soda ash as a binder in animal feeds. Condensed soybean solubles are used as the binder in animal feed blocks in U.S. Pat. No. 4,349,578, and U.S. Pat. No. 5,871,802 teaches the use of liquid by-products such as corn steep liquor and condensed distillery solubles as binders in animal feed pellets. Wheat gluten is taught as the binder for animal feed pellets in U.S. Pat. No. 5,102,671, and hydrolyzed starch is used as the binder in U.S. Pat. No. 4,048,268 for extruded animal feeds made to contain antibiotics. Another document, U.S. Pat. No. 4,976,977, teaches a combination of clay and molasses as a pelleting agent for animal feed. Collagen, an animal-derived binder, also is sometimes used as a binder.
For various reasons, the binders taught in the foregoing references are less than satisfactory. Generally, the binders taught in the foregoing references allow modest levels of fat to be incorporated into the pelleted product, but such binders are not suitable for higher fat animal feeds. Certain of the foregoing binders suffer from other drawbacks. For instance, recent outbreaks of transmissible spongiform encephalopathies, such as Bovine Spongiform Encephalopathy (commonly known as xe2x80x9cmad cow diseasexe2x80x9d) have received concerns about the safety of use of animal-derived products such as collagen in feedstocks for other animals.
At present, the most common method for providing high-fat animal feeds is to formulate a low-fat feed and to spray a vegetable fat onto the feed. However, although fat levels can be increased using the foregoing technique, other difficulties arise. For instance, the fat-covered feed is difficult to handle and transport. For these and other reasons, fat-sprayed feeds are generally unsatisfactory.
In light of the drawbacks inherent in the foregoing known binders and feeds, it is a general object of the invention to provide an animal feed that incorporates a satisfactory binder.
It has now been discovered that hemicellulose, in particular corn hull hemicellulose, possess superior properties when used as an animal feed binder. Hemicellulose, a soluble component of agricultural residues such a corn hulls and other cellulose-containing materials, is readily obtainable via the alkaline cooking of corn hulls and other corn components, as is taught in U.S. Pat. Nos. 2,801,955; 3,716,526; 2,868,778; 5,972,091; 5,855,659; 5,503,668 and 4,038,481, and in published International Application No. WO 98US/05551.
In accordance with one embodiment of the invention, an animal feed that includes a fat, the fat being present in an amount effective to provide nutrititive fat to an animal; a solid nutritive source; and a hemicellulose binder, the hemicellulose binder being present in at least an amount effective to substantially provide intraparticle cohesion, is provided. The animal feed is provided in the form of discrete plural particles of a size suitable for feeding to an animal. Preferably, the animal feed is in the form of pellets, by which is contemplated particles produced by a pellet mill in a pelletizing process.
Other features of the invention are set forth hereinbelow and in the appended claims.
The adhesive used in connection with the invention comprises hemicellulose, and most preferably comprises hemicellulose and water. Hemicellulose preferably is obtained from corn hulls, a by-product from the corn wet milling industry. Hemicellulose also can be obtained from corn bran, a by-product from the corn dry milling industry; from spent germ, also from the corn wet milling industry; or from spent germ from the corn dry milling industry. All of these products are by-products, either from the isolation of corn starch, corn protein and corn oil in the case of the corn wet milling industry, or from the isolation of corn flour and corn oil in the case of the corn dry milling industry. Because of the high hemicellulose content in corn hulls and the ready availability of corn hulls, corn hulls are the preferred source for hemicellulose used in conjunction with the invention. Other suitable sources for hemicellulose include other seed sources, such as wheat, oats, and soybeans. Most preferably, the adhesive composition includes the liquid fraction resulting from alkaline cooking of a hemicellulose-containing agricultural residue, which most preferably is a corn hull residue.
Hemicellulose is present in the animal feed in any amount effective to improve intraparticle cohesion as compared to a similar particle made without the hemicellulose. Generally, the animal feed particle will be deemed to have sufficient intraparticle cohesion when the particle is suitable for ordinary transport and use as in animal feed. Most preferably, the intraparticle cohesion is such that the feed has a durability no greater than 2.0, as determined via analysis with a RoTap sieve shaker (as set forth in more detail in Example 6). To achieve a feed with this level of durability, the hemicellulose preferably is present in the animal feed in an amount ranging from about 0.2% to about 10% by weight of the animal feed. More preferably, the hemicellulose is present in an amount from about 0.5% to about 8%; even more preferably, an amount ranging from about 1% to about 6%; and even more preferably, an amount ranging from about 2% to about 4%.
The animal feed composition further includes a fat. It is contemplated that any animal and/or vegetable fat may be useful in conjunction with the invention. Suitable examples of vegetable fat include corn oil and soy oil. For instance, in one embodiment of the invention, full-fat corn germ is used as a starting material in fabricating the animal feed. An example of a suitable animal fat is choice white grease, a swine-derived fat. However, particularly in light of the growing concern over incorporation of animal by-products into animal feeds, preferred embodiments of the invention do not include animal fat.
The fat may be present in the animal feed in any amount effective to provide nutritive fat to the animal. It is contemplated that the fat content may vary depending upon the animal or upon the intended nutritive qualities of the feed. Generally, it is preferred that the fat is present in the animal feed in an amount of at least 5% by weight of the feed. More preferably, the fat is present in an amount of at least about 10%; even more preferably, an amount of at least about 15%; even more preferably, an amount of at least about 17%; even more preferably, an amount of at least about 20%; and even more preferably, an amount of at least about 25% by weight of the animal feed. It is contemplated that two or more fat sources may be included in the feed; if such is the case, the total fat amount preferably falls within one or more of the foregoing ranges.
The animal feed further includes a solid nutritive source. Any suitable solid nutritive source may be used in conjunction with the invention, and thus, for instance, the solid nutritive source may comprise a whole grain, such as whole wheat, whole rice, whole corn, or whole barley. The solid nutritive source alternatively may comprise a nutritive grain fraction, such as nutritive wheat, nutritive rice, nutritive corn, or nutritive barley fraction. Other nutritive sources include those derived from soy, oats, sorghum, and the like. The nutritive source may include other nutritive sources, including sources (such as molasses solids) that are initially provided in liquid form. The solid nutritive source may be present in the animal feed in any suitable amount. In the case of a somewhat low-fat feed, it is contemplated that the solid nutritive source may be present in an amount of 95% or greater. In more preferred embodiments of the invention, the solid nutritive source is present in an amount of at least about 60%, more preferably, an amount of at least about 70% by weight of the animal feed.
It is highly preferred that the nutritive source include a protein source, which may be present in any amount effective to provide protein to the animal. Protein preferably is present in an amount ranging from about 5% to about 40% by weight of the animal feed. Young swine are particularly needy of protein, and protein contents in the upper portion of this range (e.g., a protein content of about 36%) are preferred in feeds intended for such swine. More preferably, for feeds for other animals, the protein is present in an amount ranging from about 10% to about 30% by weight of the animal feed; even more preferably, the protein is present in an amount ranging from about 15% to about 20% by weight of the animal feed.
It is further preferred that the animal feed include a fiber source. Generally, sources of fiber, such as soybean hulls, rice hulls, corn hulls, cottonseed, wheat hulls, and the like are considered largely non-nutritive (at least in the case of non-ruminant animals). In any case, regardless of whether the animal feed is intended for use by ruminants, the feed preferably includes such fiber source in an amount effective to provide fiber to the animal. Different feed formulas for different animals vary greatly in the amount of fiber desired. Preferably, the fiber source is prepared in an amount ranging from about 1% to about 25% by weight of the animal feed, the percentage being expressed by the bulk weight of the hulls or other source.
In any event, the feed may further include additional materials. For instance, the feed may include one or more vitamins or nutritive minerals, or, more generally, any other suitable nutritive source or other suitable ingredients. As but one example, the feed may include one or more antibiotics.
All of the foregoing ranges are intended to provide general guidelines as to the amount of ingredients suitable for use in the compositions of the invention. The actual composition of an animal feed may vary, depending on factors such as the type of animal and the desired levels of fat, fiber, nutrients, and other materials.
The animal feed may be prepared by any method known in the art or otherwise found to be suitable. Generally speaking, the animal feed is prepared by combining the ingredients of the animal feed to form a mixture, and forming discrete plural particles of the animal feed from the mixture. Most preferably, the particles are formed by pelletizing the mixture. Those skilled in the art of pelletizing will appreciate that various conditions may be employed during the pelletizing process. Generally speaking, moisture levels in the pellet mill may range from about 5% to about 12%, with a product temperature ranging from about 120xc2x0 F. to about 250xc2x0 F. In the preparation of one horse feed, for instance, the pelletizer was operated under the following conditions:
The size of the pellets preferably ranges from about {fraction (1/16)} in. to about 1 in. Preferably, when the feed is intended to a larger animal such as a horse or cow, the size ranges from about xe2x85x9 in. to about {fraction (5/32)} in. When the feed is intended for a smaller animal, such as a rabbit or a small dog, the size of the pellets preferably ranges from about {fraction (3/32)} in. to about xe2x85x9 in. The size may be controlled by selecting a die of appropriate dimensions.
The animal feed need not be provided to an animal in any special form, but, in preferred embodiments, the feed is simply fed to an animal. It is contemplated, for instance, the animal feed may be useful in conjunction with the feeding of a horse, a cow, a sheep, a pig, a rabbit, a guinea pig, a gerbil, a cat, a dog, and more generally, any other animal. It is further contemplated in some embodiments that the product of the invention may be provided in a form intended and suitable for human consumption, i.e., that the xe2x80x9canimalxe2x80x9d is a human and that the xe2x80x9cfeedxe2x80x9d is a foodstuff intended for human consumption (e.g., an energy bar). It will be appreciated that both the composition of the animal feed and the size of the particles will be expected to vary depending on the animal for which the feed is intended. In any event, other ingredients, such as colorants, flavorings, and the like may be incorporated in the feed.
The following Examples are provided to illustrate the invention, but should not be construed as limiting in scope.